Jumat, 17 Desember 2010

Organ-Organ Tumbuhan

The main organs of plant seeds there are 3, namely: roots, stems, and leaves.Who's the other parts of these organs is a modification, eg modifications tuber roots, flowers modification of twigs and leaves.

ROOT

Root is the root origin of the institution (radix), in dicots, the root of the institution continues to grow so as to form the roots of riding, in monocots, the root of dead bodies, then at the base of the stem will grow roots that have a similar size that form the root fibers.

The roots of monocots and dicots root tip is protected by a hood or kaliptra, whose function is to protect the root tip when penetrating the soil, there kaliptra cells containing beads of Amylum, called kolumela.

In young roots when it's done cross-section will look the parts from outside to inside.
a. Epidermal
b. Cortex
c. Endodermis
d. Cylinder Head / Stele

a. Epidermal
The composition of the cells meeting and thick single layer of cells, easily pass the cell wall of water. Root hairs is a modification of the root epidermal cells, is responsible for absorbing water and dissolved mineral salts, root hairs extending root surface.

b. Cortex
It lies directly beneath the epidermis, the cells are not arranged a meeting so many have a space between cells. Most are built by parenchymal tissue.

c. Endodermis
Is a separator layer between the cortex by the central cylinder. Endodermis cells can undergo thickening agent cork on the walls and formed like dots, called point Caspary. In the subsequent growth of thickening agents on the cork until the cell wall facing the central cylinder, when examined under a microscope would look like hutuf U, called U-cells, so that water can not go to the central cylinder. But not all endodermis cells have thickened, allowing water to enter the central cylinder. The cells are called cell router / cell impregnation.

d.Silinder Center / Stele
Cylinder head / Stele is the deepest part of the root.
Consisting of various kinds of networks:
- Persikel / Perikambium
Is the outermost layer of the Stele. Branch roots formed from the growth persikel outwards.
- File Tubes Transport / Vasis
Consists of xylem and phloem are arranged alternately in the direction of the toes. In dicotyledonous between xylem and phloem cambium tissue there.
- Core It lies most within or between beam transport vessels consists of parenchymal tissue.

STEM

There is a difference between dicotyledonous and monocot stem anatomy in the composition.

Trunk Network

1. Dicotyledonous stem
In dicotyledonous stems are the layers from the outside in:

a. Epidermal
Consisting of a compact cell membranes, has no space between cells. The function of the epidermis to protect the underlying tissues. On the stem secondary growth, the epidermal layer was replaced by a layer of cork cambium formed from cork.
b. Cortex
Stem cortex is also called first shell, consisting of several layers of cells, which is close to the epidermal layer is composed of kolenkim network, composed of increasingly into the parenchymal tissue.
c. Endodermis
Endodermis rod also called skin deep, composed of a layer of cells, a layer of separation between the cortex with the Stele. Endodermis Anguiospermae plants contain starch, but not found in gymnosperms plant endodermis.
d. Stele / Cylinder Head
It is the deepest layer of the stem. Outermost layers of the Stele called perisikel or perikambium. Stele Institute of vessels on the type of collateral, called xylem and phloem meaning. The location of each side by side, next to the xylem and phloem of the outer. Between xylem and phloem cambium intravasikuler there, on the subsequent development of parenchymal tissue contained between the beam transport vessels are also turned into cambium, called the cambium intervasikuler. Both can hold secondary growth resulting in increase of trunk diameter. In dicotyledonous plants, woody hard, and his chronic, secondary thickening growth is not continuous, but only when water and nutrients is enough, while the dry season so that growth does not occur on the trunk appear thickened growth layers, each layer shows growth activity for one year, layer upon layer of the circle is called the Circle of the Year.

2. Monocot stem
In monocot stems, the epidermis consists of a single cell layer, the boundary between the cortex and the Stele generally unclear. In Stele monocots have vascular bundles that spread and type of collateral closed meaning between the xylem and phloem cambium was not found. The absence of cambium in monocots monocotyledon not cause the stem to grow bigger,in other words there is no secondary thickening growth. However, there are monocots which can hold the secondary thickening growth, for example on HANJUANG tree (Cordyline sp) and pineapple trees across (Agave sp.)

LEAF

anatomy-leaf

Leaf is a modification of the stem, the plant is part of the body's most lots contain chlorophyll, so photosynthesis activity most widely held in the leaf.
Anatomy of the leaf can be divided into 3 parts:
1. Epidermal
The epidermis is the outermost layer of leaves, there are upper epidermis and lower epidermis, to prevent the evaporation that is too large, the epidermis layer is coated by a layer of cuticle. In the epidermis there are stomata / leaf mouth, stoma useful to the site of a gas exchange to and from outside the body of plants.
2. Parenchyma / mesophyll
Leaf parenchyma consists of 2 layers of cells, the palisade (fence networks) and sponge (sponge tissue), both containing kloroplast. Rail network cells are tightly sponge tissue cells rather tenuous, so there are spaces between cells. Photosynthetic activity is more active on the fence because kloroplastnya network more than the sponge tissue.
3. Tubes Networks
Leaf vascular tissue is a continuation of the stem tissue, bone contained in the leaves and leaf veins.